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Felty's syndrome is a rare, potentially serious disorder that is defined by the presence of three conditions: rheumatoid arthritis (RA), an enlarged spleen (splenomegaly) and a decreased white blood cell count (neutropenia), which causes repeated infections.[1] Although some individuals with Felty's syndrome are asymptomatic, others can develop serious and life-threatening infections.[2] Symptoms of Felty's syndrome, in addition to those associated with the three conditions stated above, may include fatigue, fever, weight loss, discoloration of patches of skin,[1] mild hepatomegaly (enlarged liver), lymphadenopathy (swelling of lymph nodes), Sjögren syndrome, vasculitis, lower-extremity ulcers, and other findings.[2] The exact cause is unknown, but several risk factors have been proposed, including autoimmunity.[1][2] A few familial cases of the condition have been reported.[3] Treatment typically focuses on controlling the underlying RA; immunosuppressive therapy for RA may improve neutropenia and splenomegaly.[2]

Last updated: 1/6/2011

What causes Felty's syndrome?

The exact cause of Felty's syndrome is unknown, although several causes and risk factors have been proposed. Some experts believe it may be an autoimmune disorder, and that it may sometimes be inherited in an autosomal dominant manner.[1] Other proposed risk factors have included:

aggressive and erosive synovitis (inflammation of the tissue that lines the joints)

HLA-DR4 positivity (having a specific gene for the immune system that is associated with RA) and DR4 homozygosity (having 2 identical copies of this gene)

extra-articular RA manifestations (symptoms that are not joint-related)[2]

Last updated: 1/6/2011

Is Felty's syndrome inherited?

It has not been concluded that Felty's syndrome is an inherited condition; most individuals with Felty's syndrome have not had a history of the condition in their family. However, there have been a few reports of the condition appearing to be familial. Furthermore, although the condition itself may not be inherited, some of the risk factors associated with Felty's syndrome may have genetic components. One study found that a family history of rheumatoid arthritis was more common in patients with Felty's syndrome and that there was a strong association with HLA-DR4 (an immune system gene common in individuals with RA). The authors also stated that there was an increased frequency of another gene as well, suggesting that certain other immune system genes may interact with HLA-DR4 and contribute to individuals developing Felty's syndrome.[4]

In another report, the authors described a family in which 3 siblings had Felty's syndrome. All of the siblings shared a specific haplotype (a group of immune system genes that may be inherited together). The authors stated that they believe this supports the theory that multiple genetic factors are involved in family members being predisposed to Felty's syndrome.[3]

An earlier article described a family in which the mother and 2 of her 5 children had Felty's syndrome, which suggested autosomal dominant inheritance (which has not otherwise been reported).[5]